Infections are bad because the virus transmits. The virus is capable of mutating to evade the immune response. Future variants may also attack different body systems. For example, it looks like BA.5 reverts back to the lungs vs the original omicron variant.
Also, it is quite unfortunate that we now have evidence that multiple acute covid infections may cause long lasting health problems.
Which to be honest is the wrong metric to look at. The right metric is whether you get sick from it. If previous infections or vaccinations downgrade the virus to just a cold, then it’s good enough. Clearly we have no mean to stop this virus, not even slow it down. But if it is mostly harmless, is that really a problem?